Process for hydrocarbon conversion



May 23, 1946. K. H. HAC'HMUTH ETAL '2,401,242

l PROCESS FOR HYDROCARBO-N CONVERSION 'Filed 001'.; 3, 1942 Patented Mayu UNITED'STATES PATENT orrica PROCESS 'FOR HYDROCARBON CONVERSION Karin. nochmuth, Borucs'vuic, om., and novia G. 'Blaken Missiomlians.,assignors to Phillips Petroleum Company, a corporation oi' DelawareApplication October 3, 1942, Serial No. 460302 12 claims. (ci. 26o-esas)'I'his invention relates to hydrocarbon conversionv processes utilizingsludge-forming metal halide catalysts of the Friedel-Crafts type. Moreparticularlyl it relates to the utilization of v metalhalide-hydrocarbon sludges formed in hydrocarbon conversions such asisomerization and alkylation reactions catalyzed by aluminum chloride,aluminum bromide, and the like.

Of great comercial interest at the 4present time are the isomerizationand alkylation o! lowboiling hydrocarbons, particularly members of theparailin series such as the butanes and pentanes. In .these reactions, asimple chemical change is effected under relatively mild conditions. Inthe case of isomerization, a change in carbon skeleton`without change innumber of carbon atoms occurs, and in the case of alkylation. the directunion of two molecules, such as an isoparaiiln and an olen, occurs toproduce a higher molecular weight saturated hydrocarbon. These reactionsare known to be catalyzed in a greater or lesser extent by the so-calledFriedel- Crafts catalysts, among the better known of which may bementioned aluminum chloride, aluminum bromide, boron iluoride, zincchloride,

ferrie chloride, antimony triiiuoride, and other' Aluminum chloridepolyvalent metal halides. has as to date received the greatestcommercial acceptance due to itsactivity, relatively low cost,

and availability. Accordingly. because of its importance, and ior thesake of convenience we shall describe our invention with particularreference to the-isomerization of normal butane to isobutane-ascatalyzed by aluminum chloride. Application oi the invention to othersimilar. hydrocarbon conversions, using aluminum chloride or otherFriedel-Crafts type metal halide catalysts* which form sludges under theconditions oi operation, will be apparent to those skilled inthe art inview of the detailed ldisclosure to fallow.

' In an isomerization process utilizing anhydrous aluminum chloride as acatalyst, the catalyst may be charged to the process either as a solidor as other suitable liquid. In either case, ay liquid sludge isproduced after a short period of operation. We have :found thatordinarily' the sludge at the outset is active, as a catalyst andgradually nomic advantage. j

In general. reference in this application to sludges refers primarilyto'sludges formed by contact of the hydrocarbon reactants with lumiynumchloride. rather than to suspension or slurries of aluminum chlorideprepared for direct l use as a primary catalystfalthough the sludges mayhave appreciable quantities of aluminum chloride dissolved and/orsuspended therein. Such sludges are relatively free from asphaltic o'rtarry'materials and are utilized according to our invention at mildconditions oi temperature similar to those used in the reaction zoneproper.

Aluminum chloride and other Friedel-Crafts catalysts are relativelyvolatile, and may also exchamber along withthe isomerization products.

a slurry with considerable aluminum chloride disl solved and/orsuspended in hydrocarbons or hibit appreciable solubility in liquidhydrocarbons. This volatility and solubility give rise to seriousoperating diiiiculties, particularly `in continuous processes. Theisomerization of butane f may be carried out with the hydrocarbon in theliquid' or gaseous phase, the latter being more often used'. Small butappreciable quantities of aluminum chloride are carried out of thecatalyst 'Ihis aluminum chloride is deposited in the transi'er lines,valves. and other parts of the equipment, particularly at points oflower temperature than that obtaining in the catalyst chamber.

These deposits of aluminum chloride require frequent shut downto enabletheirremovaLwii-.h consequent loss of plant capacity and the expenditureof otherwise unnecessary labor. The corrosive eiiects of the aluminumchloride are also frequently serious, particularly in the valves andpumps. It is also difcult to obtain products of the process free fromaluminum chloride, which may interfere with subsequent use of suchproducts. l

Aluminum chloride sludge has been found to bc highly corrosive-to mostordinary metals and other material of construction when in motion. Theuse oi' such sludge as by circulating it at relatively high rates ofiiow; bubbling gaseousreactants through it.,or subjecting thesludge inother-ways to violent agitation would cause severe erosion and/orcorrosion problems from motion' of the sludge.

It is an object of this invention to provide for improvednon-destructive hydrocarbon reactions wherein a Friedel-Craftsv typemetal halide is used as catalyst under relatively mild conditions'.Another object is to provide for theutilization of metal halide sludgeformed during such reactions. A further object is to provide forcarrying out such hydrocarbon conversions as isomeriza- -tion,alirylation, and the like.-with aluminum Vhalide and similar relativelyvolatile catalysts.

Yet another object is to utilize the catalytic activity of aluminumchloride-hydrocarbon sludges. A still further object is to remove fromthe hydrocarbon. eilluents from the catalyst zone the the aluminumchloride carried over in the cata lyst chamber eiiiuents, thuseifectively diminish-y ing or stopping entirely the carry-over intoother parts of the plant equipment. We may thus use for a useful purposethe sludge which might otherwise be wasted. A preferred aspect of ourinvention involves the use of sludge in such a manner 'as to avoidsevereerosion and/or corrosion problems from motion of the sludge.

In one aspect our invention comprises first subjecting low-boilinghydrocarbons to be treated to conversion in the presence of aluminumchloride or other similar catalyst. During the conversion a sludge isformed which may or may not exhibit catalytic activity, depending uponreac tion conditions, etc. The total eiiluents from the conversion stepare then brought into contact with the sludge, various manners ofaccomplishing this being described'in detail below. This contacting ofeilluents and sludge, in the case wherein the sludge retains somecatalytic activity, will cause further conversion to occur and at thesame time spend the sludge to partial or complete exhaustion ofactivity. Simultaneously, the small but important amount of aluminumchloride hereinabove referred to which is carried away from the catalystby the efliuent reactants, is removed readily by the sludge byabsorption or solution. In the 'case wherein the sludge does not have-much or any catalytic activity, it acts to remove the residual aluminumchloride from the reactants, being even more efiici'ent in this respectvolatilized -and/or dissolved metal halide catalyst i chloride catalystzone, there are opposing factors tending to change the activity of thesludge.

' Continuante of the catalyzed reaction tends to than sludge havingappreciable catalytic activity.

It is in fact preferable that the last portions of sludge contacted bythe eiiiuents should have no substantial activity as a catalyst; thisensures the most complete removal of residual aluminum chloride, as willbe explained below.

We have found that the aluminum chloride sludge will very readilydissolve or otherwise take up large quantities of aluminum chloride. In

fact, there appears to be no limit to the quantity of aluminum chloridethat can be dissolved in such a sludge except for the practicallimitation that at any particular temperature the sludge will becomemore and more viscous as more aluminum chloride is dissolved thereinuntil finally a point is reached where the viscosity of the sludge is sohigh that it becomes impractical' to handle it at that temperature. Athigher temperatures the same sludge willcbecome quite iluid again and'capable of dissolving-more aluminum chloride.

However, we have found that such. a sludge which has taken up' aconsiderable amount of aluminum chloride will no longer give as completea removal of volatilized aluminum chloride from the reacthe reactionproducts 'with substantially Spent sludge.

-spend the sludge, while absorption or solution of carried-over aluminumchloride tends to activate the sludge.' These factors must be consideredin any particular situation to obtain the optimum conditions forutilizing to the fullest ex- .tent possible, consistent with economicoperation,

any catalytic activity available while ensuring nal substantiallycomplete removal of alumin chloride from the eiiiuents of the process.This may readily be done by one skilled in the art by following theteachings of the present disclosure,

suitably modied for the particular process in presence of the reactionproducts. Buch olens i or the like serve to ki11" the sludge rapidly,than permitting complete removal of residual alumi num chloride from thereaction products. Tala method of ensuring complete removal oi activemetal halides such as aluminum chloride from hydrocarbons is describedand claimed broadly in the co-pending application of Karl H. Hacia:muth, Serial No.`460,703, iiled October 3, wat. In the isomerization ofnormal butane to isobu tane, for example, we may use butylene or otherlow-boiling olens for this purpose, injecting them into the stream ofreaction zone emuenta before or during nallcontactlng of such eiiuo entswith sludge. Only a very small proportion of butylenes need be used, andthe butylenes are not entirely wasted, inasmuch as they act aselkylating agents and react at least partially with. isobutane to giveiso-octane, which may subsequently be recovered.

Temperature and pressure conditions used in our process are mild so thatno extensive decontposition occurs, being ordinarily the conventionalconditions for the various types of conversions tc which the inventionmay be applied. ln moet cases temperatures in the sludge contacting acneor zones will be no higher than those maintained in the principalreaction zone. It will frequently be desirable to operate below thereaction zone temperature in order to effect ready condensation as wellas solution of the aluminum chloride vapors in the eilluent productsfrom the reaction zone.

Sludge expelled from a system involving this invention may be sent tosludge disposal, to a process for recovery of aluminum chloride, or iithe sludge has become sufficiently activated with dissolved aluminumchloride, it may be returned to the reaction zone as a catalyst and/orused in another contacting stage to utilize its activity.`

In general,` sludge formed in a ilrst reaction chamber containing solidaluminum chloride, which sludge may or may not have catalytic activity,is passed to a second chamber or a series of chambers packed withceramic rings or other suitable packing, in such manner that the slur'cev:3,401,942 y j I 3 distributes itself over the packing to give a highlyextended surface. By this arrangement the motion of the sludge at thewalls of the containing vessels is reduced to a minimum. the ow rate ofsludge through the apparatus is slow. and consequently the erosionand/or corrosion is reduced sufficiently to permit the use of ordinarymaterials of construction. Accordingly, the use of.`

sludge, and the amount of aluminum chloride carried out of the rstcatalyst chamber by the eiliuents therefrom. 'Ihese factors in turn are`dependent on the type of reaction being catalyzed. l

The accompanying, drawing and description thereof are provided for thepurpose of better illustrating and exemplifying the invention, and showtwo different ways of carrying out a butane isomerization process.Numerous other modifications may be used, for carrying out variousreactions, by following the teachings of this disclosure, and noparticular limitations are therefore implied.

Figure 1 shows in diagrammatic form one ar rangement of apparatuswherein the sludge and hydrocarbon effluents are passed countercur-Arently in two chambers arranged in series. Figure 2 shows anotherarrangement-wherein-sludge and reaction zonefeiiiuents are contractedconcurrently, first in one chamber and then in another, with olefinsbeing added between the two chambers to kill" the sludge. Anotherfeature of the arrangement shown in Figure 2 is the contacting ofhydrocarbon feed to the catalyst chamber withsludge before its contactwith solid pane, along with activating amounts of anhydrous hydrogenchloride or other activating agent, is introduced into the bottom ofcatalyst The hydrogen chamber I through -conduit 4.

I and is continuously withdrawn into receiver l from which it istransferred via conduit i into the top of Vchamber 2. The gaseouseiiluent from chamber I, which compriseslsobutane, normal butane,hydrogen chloride. lighter gases and small amounts of volatilizedaluminum chloride, is passed from the top of chamber I into the bottomof chamber 2 by means of conduit 'I.

Chamber 2, and also chamber 3, are filled with ceramic ware rings orother suitable type packing. 'I'he liquid sludge flows downwardlythrough the chamber and is distributed over the surfaces of the packingso that a highly extended surface of sludge is thus presented to thegases passing through the chamber. I'he conversion of normal butaneA to-isobutane continues in chamber 2. due to the activity of the sludge,although generally at a considerably lower rate than the reaction inchamber I. Furthermore, the residual aluminum chloride in the gases fromconduit `I is absorbed and/or dissolved in the sludge in chamber 2.

The sludge reaching the bottom of chamber 2 will have more or lesscatalytic activity remaining. dependent upon the relationship of `theamount of aluminum chloride taken up from the gases and the amount ofdeactivation'occurring due to continued hydrocarbon conversion, etc.'I'he contact time may be so lengthened in chamber 2 that the gaseouseiiluents therefrom are substantially free from aluminum chloride inwhich case an additional contacting chamber will not be needed.Frequently, however. it ismore desirable to provide chamber 3, which issimilar aluminum chloride. In both figures portions of chloride may beintroduced into the vreaction zone in other ways if desired, and inmost'cases will comprise from 3 to l5 mol per cent of the feed. ChamberI is operated at a pressure of to chamber 2 in construction andfunction.

In such case, the sludge from chamber 2. which accumulates in receiver8, is passed via conduit 9 into the top of chamber 3, wherein it againbecomes distributed over the. packing to provide a large surface area.The eilluent hydrocarbons, hydrogenr chloride, and traces of aluminumchloride, from chamber 2, pass into the bottom of chamber@ by way ofline I0. The gases so introduced into chamber 3 pass upwardlytherethrough countercurrently to the sludge, and pass out to furthertreatment. separation or the like via conduit I2. Spent sludge is takenfrom the bottom of chamber3 by line I I.

The eiliuents from chamber 3 comprise unconverted normal butane,lisobutane produced inV the process. traces of ive-carbon-atomV andheavier hydrocarbons, hydrogen chloride, and minor amounts of othergases lighter than isobutane which may have been introduced into thefeed and/or produced by side reactions.

Hydrogen .and propane are frequently used in the process to minimize`undesired side reactions 7 and maintain catalyst life. 'I'he Aamount.of

100 to 150 pounds per square inch gage and a temperature of about 200 F.Thefeedbeing introduced through conduit I is heated'to the approximatereaction temperature by means not shown. If necessary. the butane isdehydrated before introduction to the catalyst. The ow rate willgenerally be between aboutul to 2.0 liquid volumes of hydrocarbon feedper volume of catalyst chamber per hour. Catalyst chamber Icontainsjpi'eces of solid anhydrousalulminum chloride of about 20 meshor larger.

may also containsupported aluminum chloride catalyst.

y Afterthe process has been in operation a short time a liquid sludge isformed which usually contains appreciable amounts of aluminum chloridethat isstill active as an isomerization catalyst.

' Thisfsludge runs down tothebottom of chamber Chamber I propane usedmay be as high as ten per cent or more. while smaller volumes ofhydrogen are vusually used, if at all. It will be understood that theeiiiuents 'from the process-as just de`j scribed may be subjected to anyof the separat-` ing or other steps known to the art. These,

usually include separation of hydrogen chloride, propane, andunconverted Y normal butane. which are recycled to catalyst chamber I'.VVar-- ious 'other expedients .which are known to the art may of coursebe utilized as particular circumstances indicate.

Due to contact with'the sludge in chambers 2 and 3, the products in lineI2 contain a higher proportion of isobutane than those in line 1, and

. are substantially free from residual aluminum chloride, which makesjpossible their further treatment without encountering the .troublesomecondensausn or aluminum cmoridem unes I lthe bottom of chamber I throughline t, and leaves the top through line l. Sludge formed during lthereaction flows downwardv over the packing in the lower part of thechamber and thus comes in contact with the incoming feed before saidfeed is contacted with the solid catalyst. Such anarrangement ofcatalyst and packing, and the process of contacting the feed first withsludgeand then with the solid catalyst, are disclosed and claimed in theco-pending application of Frederick C. Neuhart, Serial No. 460,854,filed October 5, 1942, and thus do notform a part ,of the presentinvention except in combination as described with various aspects of ourinvention.

The sludge in contacting the incoming normal butane in the lower part ofreaction chamber I effects a preliminary conversion of the butane andloses a considerable part of its catalytic activity in so doing. Thissludge is then passed from the bottom of chamber I to the top of chamber2 by means of line 6, and distributes itself, over the packing containedin that chamber. The eiiiuents in linev 1` also enter the top of chamber2, and pass downward therethrough concurrently with the sludge Ifdesired, the flow of sludge and reactants may be countercurrent insteadof concurrent in chamber 2.

ascissa unsaturated hydrocarbons, may be used if desired. v

The total eiiluent is passed from the bottom of chamber 3 via line i4 toseparatorl from which spentsludge is removedthrough line Il, ,while Ltheconverted hydrocarbons, hydrogen chloride,

etc. now free from aluminum chloride, pass out through line l2 tofurther conventional treatment. Heavier hydrocarbons formed by reactionof the bfutylene may be separated out in unit i5 or otherwise, andrecovered for use as desired. i,

Frequently a uid catalyst is used instead of solid aluminum chlorideinthe primary reaction zone. This catalyst is usually a sludge or slurryprepared by suspending a relatively large amount of aluminum chlorideinliquid hydrocarbons of one kind or another, and may comprise ahydrocarbon-aluminum chloride complex with or without additionalv freealuminum chloride. For example, a slurry containing aluminum chloridesuspended in liquid hydrocarbons may be used for alkylation,particularly the alkylation of isoparainns with oleins. a process, aside stream of sludge, or a stream of spent sludge, is used for thesupplementary contacting of reaction chamber effluents in practicingthis invention. This and many other applications, using" aluminumchloride or other Friedel-Crafts type catalysts are encompassed withinthe scope of our-invention.

We claim:

1. A process for isomerizing saturated hydrocarbone which comprisescontacting saidL hydrocarbons with. a sludge-forming metal halideisomerization catalyst of the Friedel-Crafts type to edect isomerizationof lsaid hydrocarbons, and

Reaction continues in this second chamber to a greater or less extentdepending upon the activity of the sludge entering, the aluminumchloride in the vapors entering. and the contact time and conditions, asdescribed above. Frequentlyk the sludge entering chamber 2 in thearrangement shown in Figure 2 will have very little activity, and due tothe aluminum chloride picked up, willleave the bottom of chamber 2through line 9 more active than when it entered. In any case, when it isdimcult or impossible to effect 4the complete absorption of aluminumchloride from the vapors, the sludge and vapors are passed on intochamber 3, which-may be similar to chamber 2, via lines 9 and i0respectively.

vIn order to ensure a hydrocarbon emuent from the process free fromaluminum chloride, a rela- I tively small volume of butylenes isinjected into line I0 from line i3, or otherwise introduced into chamber3. Inthe presence of the valuminum chloride at 'least part of thebutylene reacts with isobutane to give branched-chain -carbon-atomparamos; The principal function of the butylenes,` however, is todeactivate the aluminum chloride and/or sludge. entirely so that thelast traces of aluminum chloride vapors will be removed from the gaseousreaction mixture, and the quantity of butylenes so introduced is madesuiilcient to accomplish this purpose. As stated, this quantity issmall, -much less' than one percent, based on the hydrocarbons in thereaction mixture, irequentlyV being suiiicient, Vwhile a few per cent isthe maximum that would ordinarily `be required' Of course itis/understood that other olednscontacting total hydrocarbon eiiiuentsfrom said contactingstep with a catalyst consisting essentially ofactive metal halidesludge formed in said step and substantiallydifferent in composition from said catalyst used in said step to utilizecatalytic activity of said sludge and obtain further isomerization.

2. The process of claim 1 in which said sludge is distributed over aninert packing material thus presenting an extended surface of sludge tosaid hydrocarbons.

3. The process of claim l in which said saturated hydrocarbons compriseessentially lowboiling normal paramns and said metal halide is aluminumchloride.

4. A process for the isomerization of normal butane which comprisespassing an anhydrous gaseous mixture comprising a major proportion ofnormal butane admixed with minor proportions of hydrogen chloride into arst chamber containing a solid anhydrous aluminum chloridecatalyst atconditions of temperature. pressure and contact time to give asubstantial yield of kisobutane, passing a liquid comprising aluminumchloride sludge formed in said first chamber as an essential componentthereof and substantially dierent incomposition yfrom said catalyst insaid first chamber to a contacting zone comprising at least one other.chamber containing a packing` material over which said sludge becomesdistributed, passing gases from said first chamber into said contactingzone to contact with said sludge i '-prppy 1ens, brother v'ze toseparatingmesnsrsepaa tins isobutane. and

In such recycling hydrogen chloride and unconverted nora mal butane to.said rst chamber. Y

5. The process oi' claim 4 in which said contacting zone consists of twosimilar chambers, and in which said sludge and said gases passcountercurrently to each other.

6. The process of claim 4 in which a small proportion of olefins isadded to said gases subsequent to their passage from said rst chamberbut prior to their passage from Vcontact with said sludge. saidproportion being suicient to substantially deactivate said sludge andthus eiect complete absorption of aluminum chloride irom said gases.

7.' A process for effecting hydrocarbon conver` sions which comprisescontacting hydrocarbon reactants with a catalytically active metalhalide sludge produced as hereinafter described, where-V vby somereaction occurs land the sludge becomes at least partially deactivated,then contacting Ago said hydrocarbon reactants aref at least partiallyfreed of4 said metal halide incorporated therein. .o

8. The process ot claim 'I in which said hydrocarbon conversion is aniscmei'lzation reaction, said hydrocarbon reactants are predominantlynormal butano,` said metal halide is an aluminum halide, and unsaturatedhydrocarbons in sum- 'cient amount to eect complete removal of saidsmall amounts of aluminum halide from said reactants are incorporated insaid reactants subsequent to their contact with said aluminum halidecatalyst.

9. A process which comprises contacting relatively low-boilinghydrocarbon material with'a' bed of solidanhydrous sludge-forming metalhalide catalyst of the Friedel-Crafts type under hydrocarbon conversionconditions, withdrawing vfrom said bed an active metal halide sludgeproduced therein concomitantly with said conversion, and contactinghydrocarbons. from said contacting step with said sludge underconversion conditions to' continue said conversion through i utilizationci' catalytic activity of said sludge.

l0. The process of claim 9in which said metal halide is aluminumchloride.

11. 'Ihe .process of 'claim 9 in which saidliydrocarbon conversion is anisomerlzation reaction.

` 12. The process of claim 9 in which said hydrocarbon conversion is 'analkylation reaction.

DAVID/ G, BLAKER.

KARL Elmont/fum.

Disclaimer 2,401,242.-Karl H. Hachmuth, Bartlesville, Okla., and DavidG. Blaker, Mission, Kans. PROCESS Fon HYDROCARBON CONVERSION. Patentdated May 28, 1946. Disclaimer led Feb. 11, 1949, by the assignee,Phillips Petroleum Company. Hereby enters this disclaimer to so much ofclaims 9, 10, 11, and 12 of said patent as may be construed to includeany intermediate separation of hydrocarbon product between said bed ofsolid catalyst and said sludge.

[clal Gazelle March 29, 1.949.]

